The present invention relates to an information recording apparatus and an information recording method for recording so-called multimedia information, including audio information such as a speech or music, video information obtained from a camera or a video device and digital code data obtained from a personal computer or a word processor, on an information recording medium such as paper in the form of an optically readable two-dimensional code pattern.
A printer apparatus has widely been used as means for recording information on a recording medium such as paper.
Such a printer apparatus generally comprises a CPU 10, a ROM 12, a sheet record information input unit 14, a RAM 16, and a printer engine 18.
The CPU 10 controls the entire printer apparatus. The ROM 12 stores programs for the CPU 10 and parameters for setting operations. The sheet record information input unit 14 is used to input sheet record information to be recorded on an information recording medium sheet, for example, characters, figures, tables, images, etc. The RAM 16 includes a record pixel information memory 16A for converting sheet record information, i.e. bit information, input from the sheet record information input unit 14, to image information, and temporarily storing the converted image information.
The printer engine 18 records the record pixel information temporarily stored in the record pixel information memory 16A on the information record medium sheet. The printer engine 18 comprises a recording head 18A and a control unit 18B for controlling the operation of the recording head 18A. The controller 18B comprises a paper sheet transfer controller for transferring paper and a head scan controller for scanning the head.
As is shown in FIG. 2, the recording head 18A includes 200 recording sections 18A1 in units of a record pixel, and each recording section 18A1 is aligned and physically fixed. A head scan controller 18B1 of the controller 18B includes guide rails and a driver for scan-driving the recording head 18A in a direction perpendicular to the direction of alignment of the recording section 18A1. The head scan controller 18B1 scan-drives the recording head 18A and records record pixels on the surface of an information record medium or paper sheet 20. A paper sheet transfer controller 18B2 of the control unit 18B moves the sheet 20, thereby effecting recording on one page.
An image recorded by single one-way scan of the recording head 18A is termed "division image 22," the head scan length in the head scan direction is "effective print length 24," and a head scan width 26 in a direction perpendicular to the head scan direction is "effective print width."
Such division image 22 is recorded several times while the sheet 20 is being moved. Thus, one-page recording is effected. For example, FIG. 3 shows an example in which an N-number of division images constitute an image on one page. Specifically, at first, a first division image 22.sub.1 is recorded. Then, the sheet 20 is moved by a distance corresponding to the head scan width 26, and a second division image 22.sub.2 is recorded. Again, the sheet 20 is moved by a distance corresponding to the head scan width 26, and a third division image 22.sub.3 is recorded. In this manner, the N-number of division images are recorded. That is, the recording on one page is completed when an N-th division image 22.sub.N has been recorded. Thus, an image larger than the division image 22 is recorded on the surface of the sheet.
Each division image is recorded by single one-way scan of the head. After the sheet 20 is moved, the next division image is recorded. The recording of each division image and the transfer of sheet 20 are performed alternately, and thus the recording on one page is effected.
FIG. 4 shows a storage structure of the record pixel information memory 16A in the RAM 16. In the record pixel information memory 16A, a one-bit memory area is assigned to one record pixel and thus information corresponding to the record pixels of one page is stored. (It should be noted that a plurality of bits may be assigned to one record pixel.) If the storage content is "1", the associated record pixel is recorded. If the storage content is "0", the associated record pixel is not recorded. The record pixel information memory 16A has a two-dimensional arrangement, and includes an area corresponding to the division images 22. Note that the record pixel number in the scan direction of the recording head 18A is termed "division image pixel length 28," and the record pixel number corresponding to the scan width of the recording head 18A is termed "division image pixel width 30."
Conventionally, various media such as a magnetic tape or an optical disk are known as media for recording audio information such as speeches and music. Even if these media are mass-produced, the price per unit is relatively high and the space necessary for storing the media is large. A great amount of labor and time is needed when a medium recording speeches is sent to a specified person by mail or brought to him/her directly. The same applies to the case of sending so-called multimedia information including image information obtained from a camera, a video device, etc. and digital code data obtained from a personal computer, a word processor, etc.
In order to solve this problem, the assignee of the present invention proposes a recording system and a reproducing system in EP 0,670,551 A1 (corresponding to U.S. Pat. Ser. No. 08/407,018). This recording system records multimedia information, including at least one of audio information, video information and digital code data, on an information recording medium such as paper in the form of a two-dimensional code pattern in which dots are arranged two-dimensionally as image information or coded information which permits facsimile transmission and inexpensive mass-duplication, and the reproducing system reproduces the multimedia information recorded in the form of the two-dimensional code pattern.
FIG. 5A shows a dot code 170 as a two-dimensional code pattern disclosure in the aforementioned EP 0,670,555 A1. As shown in FIG. 5C, one block 172 comprises a marker 174, a block address 176, address error detection/correction data 178 and a data area 180 for writing of actual data. As shown in FIG. 5B, a plurality of blocks 172 are arranged two-dimensionally in a matrix, thus constituting the dot code 170. FIG. 5D is an enlarged view of a dot in data area 180.
FIG. 6 illustrates how the dot code 170 is recorded on the information recording medium such as paper by means of the printer apparatus which prints a one-page image by recording division images more than two times. The longitudinal direction of a dot code "1" 170.sub.1 is the same as the scan direction of the recording head 18A, and the longitudinal direction of a dot code "2", 170.sub.2 is the same as the direction of movement of the paper sheet 20. The dot code 170 is recorded at a position desired by the editor, which is represented by desired code position information 32. The desired code position information 32 is located at an upper left point of the dot code 170. Note that the width of the dot code 170 in the scan direction of the recording head 18A is termed "code length 34" and the width of the dot code 170 in the direction perpendicular to the scan direction is termed "code width 36."
When the image including the dot code 170 is printed and recorded by a printer apparatus capable of printing a one-page image by the recording of two or more division images, it is ideal that the dot 38 or line 40 is exactly aligned at a boundary line 42, as shown in FIG. 7. In fact, however, defective images, as shown in FIGS. 8A to 8C, are often produced at the boundary lines 42 of division images 22.
Specifically, in FIG. 8A, a pair of segments of the dot 38 and a pair of segments of the line 42, which appear on the two division images, are not joined and a blank portion lies between each pair of segments. In FIG. 8B, the segments of dot 38 and the segments of line 42 overlap each other at the boundary of the division images 22. In FIG. 8C, the upper division image and the lower division image are displaced horizontally.
Such defects of the images are attributable to mechanical precision of the head scan controller 18B1 and paper sheet transfer controller 18B2. As compared to an error of the recording head 18A in the main scan direction, an error of transfer control of paper 20 is large. If the precision of paper transfer control is low, such defects as are shown in FIGS. 8A and 8B will occur. If the precision of repetitive scan of the head is low, such a defect as is shown in FIG. 8C will occur.
As has been stated above, when the dot code 170 comprising plural division images is to be recorded, defects as shown in FIGS. 8A to 8C will occur. Such defects will not pose serious problems in the case of printing of characters, etc. However, if very fine dots are to be recorded, as in the case of the dot code 170, the dots will not be read and the original multimedia information cannot be reproduced.
Furthermore, if there is a blurring record pixel in the marker 174 or dots in the dot code 170, the dot will not exactly be read and the original multimedia information cannot be reproduced.